Fig. 1.

Comparison of ALG6 deficient cell lines. (A) HeLa cells, ALG6-CDG fibroblasts and control human fibroblasts (38 and 3348) or (B) MI8-5 cells and CHO cells were incubated with 1 mM castanospermine (CST) or solvent during 20 min of starvation and 10 min of labeling as indicated. Endogenous human (H.s.) or CHO (C.g.) prosaposin (pSAP) glycoforms were immunoprecipitated with anti-saposin D sera and resolved by SDS–PAGE. The indicated protein molecular weights shown in all figures are of prestained molecular-weight markers electrophoresed on all gels. (C) Agarose gel electrophoresis of the ALG6 coding sequence from CHO and MI8-5 cells after amplification by RT-PCR using two primer pairs. (D) Schematic representation of the Alg6 coding sequence in MI8-5 cells. The G57A mutation introduces a stop codon into both ALG6 mRNAs. The short mRNA transcript lacking exon 8 has a frameshift (FS) mutation at codon 170 followed by a nonsense mutation at codon 208.